The present application is directed to a two-dimensional tunable filter array for a matrix of integrated fiber optic input-output light channels.
A tunable filter is one of the key components in a multi-channel light wave system; e.g., a wavelength division multiplexing (WDM) system. Several microelectromechanical tunable filters have been developed. One is shown in an article entitled, xe2x80x9cMicroelectromechanical tunable filter with stable half symmetric cavity,xe2x80x9d Electronics Letters, 34, (1998), pp. 1967-1968, P. Tayebati, et al. The reported channel spacing for these devices is around 10 nm. Experiments have shown that the misalignment between the filters and their input-output couplers of fiber optic light channels were found to be about 0.25 xcexcm. Thus, this is very challenging from a manufacturing standpoint to align the discrete components (namely, a tunable filter array and a fiber array) with that tolerance.
It is therefore an object of the present invention to provide integrated two-dimensional tunable filter array for a matrix of fiber optic input-output channels.
In accordance with the above invention there is provided an integrated two-dimensional tunable filter array for a matrix of fiber optic input/output light channels incorporating microelectromechanical (MEMS) tunable filters comprising a first semiconductor substrate having a plurality of guiding grooves for such input light channels aligned in a predetermined plane parallel to the major surfaces of the substrate extending from an external portion of the substrate and terminating in an interior array in the substrate in 45xc2x0 reflecting surfaces to cause light beams of inserted light channels in the guides to be reflected 90xc2x0 from the plane. A second semiconductive chip is bonded to the first substrate and incorporates an array of tunable filters for respectively receiving the reflected light beams. A third semiconductive substrate is bonded to the second chip and has an array of guiding grooves having axes perpendicular to the major surfaces of the third semiconductive substrate for insertion of output light channels, such array matching and being passively aligned with the filter array.